Qualitative and Quantitative Analysis of Stacking Disorder in α-and β-SiC by X-ray Diffraction and Structure Modeling

1995 ◽  
Vol 410 ◽  
Author(s):  
Bogdan Palosz ◽  
Svetlana Stel'makh ◽  
Stanislaw Gierlotka

ABSTRACTA method of analysis of disordering in α- and β-SiC polycrystals by numerical modeling, and a simulation of X-ray diffraction profiles are presented. The diffraction patterns of nonperiodic structures were simulated for models of 2000 layer fragments of the structure. Computer generation of the models was based on the Poisson function describing the size distribution of the domains of basic polytypes and faults. The models were quantified by a set of input probability parameters describing relative frequencies of the occurrence of the domains of polytypes and faults. Implementation of a correlation parameter that characterizes coherence of sequential domains of a given polytype assures a good reproducibility of the simulated diffraction profiles obtained for the same set of the model parameters. Based on this method, a quantitative analysis of disordering in polycrystals of SiC annealed in the temperature range 1100–2200 °C was performed.

2021 ◽  
Vol 9 (09) ◽  
pp. 706-712
Author(s):  
Moursalou Koriko ◽  
◽  
Dodji Zounon ◽  
Agbegnigan Degbe ◽  
Sanonka Tchegueni ◽  
...  

In order to contribute to the enhancement of local materials, Aklakou clays taken from the quarry and used for pottery have been characterized from a physicochemical and mineralogical point of view. Thus, the samples taken from the quarry were subjected to chemical and mineralogical analyzes. Several qualitative and quantitative analysis techniques were used (chemical analysis, thermal analysis, X-ray diffraction and analysis by I.R. spectroscopy). These results demonstrated the richness of this quartz clay, resulting in a high proportion of silica (77.62%). This study was therefore essential before any application of this type of clay in the formulation of aggregates and pottery products or even ceramics in the broad sense. We can therefore conclude that the clays mined at the Aklakou quarry are very favorable materials for formulations of pottery products and in other fields such as the formulation of light aggregates.


1964 ◽  
Vol 8 ◽  
pp. 456-461
Author(s):  
Donald Mitcham ◽  
Biagio Piccolo ◽  
Verne W. Tripp ◽  
Robert T. O’Connor

AbstractThe application of X-ray fluorescence to the qualitative and quantitative analysis of chemically modified cotton textile materials is described. The scope and flexibility of the technique have permitted the determination of more than 20 elements with, greatly reduced elapsed time compared with the corresponding spectroscopic or wet methods. Precautions to be observed in preparing standards are discussed. Results of the analysis of typical modifications and their significance in the development of cottons for specific uses are described.


1973 ◽  
Vol 38 (3) ◽  
pp. 339-344 ◽  
Author(s):  
John W. Weymouth

AbstractThis is a preliminary report on a quantitative method for grouping prehistoric pottery using x-ray diffraction techniques. Of the various analytical methods that have been applied to the analysis of pottery, x-ray diffraction techniques have been among the least used, and then usually to obtain qualitative information. Most analytic methods measure the relative abundance of chemical elements, but diffraction patterns give information on the crystalline substances in the pottery. In this study, attention is directed to the crystalline components of the temper rather than the clays or their derivatives. The method groups pottery according to the relative concentrations of such minerals as quartz, calcite, and the feldspars. Thus, success depends on reasonable consistency in the use of tempering materials by pottery makers at one time and place. I have examined a number of sherds from different sites in Iowa and Missouri supplied by Dale R. Henning, University of Nebraska. The results so far indicate that it is possible to group prehistoric pottery by a quantitative analysis of the x-ray diffraction pattern of the temper in the pottery.


1959 ◽  
Vol 3 ◽  
pp. 337-348 ◽  
Author(s):  
J. Leroux ◽  
M. Mahmud

AbstractA theoretical approach of some factors influencing the intensity diffracted by a polycrystalline material at a definite Bragg angle has been confirmed by experimental data obtained with a high-angle Norelco diffractometer. The factors mainly considered are the focusing arrangement of the goniometer which delineates the geometric shape of the volume fraction of the sample being irradiated and the absorption of the latter.Tests have been performed (a) with quartz mixed in samples covering a large range of absorption coefficients, (b) with two different K radiations using copper and molybdenum targets, (c) with three different angles of beam divergence of 1, ½, and ¼°, respectively, and (d) with the sample packed and leveled in a copper grid with openings of about 350 μ. As this test with copper grids was to demonstrate that each opening was acting like a volume of sample irradiated by a beam of extremely small divergence (0.1°), it also shows that more accuracy in the measurement of the exact Bragg angle can be reached in these conditions as compared to that obtained with conventional sample holders.A general equation, suitable for qualitative and quantitative analysis when these factors have to be taken into consideration, is proposed.


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